Yeah, a fast professional telephoto lens makes a world of difference in photographing sports, fast moving subjects and action shots in general, but you can compensate a lot with the right settings (i.e. fast shutter speed, large aperture, AI Servo focusing, burst mode, etc). Also, consider getting a tripod (or monopod) if you haven't got one yet, it's not expensive and helps A LOT to keep your camera steady and avoid blurring.